Method and apparatus for stripping well pipes



April 1955 G. 0. JOHNSON ETAL 3,179,174

METHOD AND APPARATUS FOR STRIPPING WELL PIPES Filed June 22, 1961 4Sheets-Sheet 1 FIG.

INVENTORS:

F. BATES D. JOHNSON BY I 6 [4314c THE IR AGENT G. D. JOHNSON ETAL3,179,174

April 20, 1965 METHOD AND APPARATUS FOR STRIPPING WELL PIPES Filed June22. 1961 4 Sheets-Sheet 2 FIG.2

FIG.6

s R Q T N E V N W. F. BATES e. 0. JOHNSON 8Y1 H,7 '=C-J THEIR AGENT FIG.3

April 20, 1965 G. D. JOHNSON ETAL 3,179,174

METHOD AND APPARATUS FOR STRIPPING WELL PIPES Filed June 22, 1961 4Sheets-Sheet 3 vm ON m Om mm mm mm wm mm h wI INVENTORS F. BATES D.JOHNSON BY Q W THEIR AGENT April 20, 1965 G. D. JOHNSON ETAL 3,179,174

METHOD AND APPARATUS FOR STRIPPING; WELL PIPES 4 Sheets-Sheet 4 FiledJune 22, 1961 FIG. 14

INVENTORS:

FIG. l2

W. F. BATES THEIR AGENT United States Patent flice idihdid Patented Apr.20, i965 3,179,174 METHUD AND APPARATUS FUR STREPENG WELL FEES Glenn D.Johnson, Downey, and William F. Bates, Ar-

cadia, Calif., assignors to Shell (lit Company, New York, N.Y., acorporation of Delaware Filed June 22, 196i, Ser. No. lldfldd 18(Ilaims. (Cl. 166-46) This invention relates to a method and apparatusfor running pipe in and out of a well and pertains more particularly toa method of inserting into or removing from a well a string of pipewhich surrounds a second string a pipe of a smaller diameter or a welltool which must be mold in tension in the well'to prevent it fromdropping to the bottom of the well.

The operation of inserting a pipe into a well or removing it therefrom,when the pipe surrounds a second pipe or an elongated object alreadydisposed within the well, is commonly referred to as stripping.

In an attempt to locate new oil fields an increasing amount of welldrilling has been conducted at off-shore locations, such, for example,as oil the coast of Louisiana, Texas and California. As a generalrule/the strings of casing in a well, together with the tubing string orstrings, extend to a point well above the surface of the water wherethey are closed in the conventional manner that is used on land wells,with a conventional wellhead assembly being attached to the top of thecasing. Attempts have been made recently to provide methods andapparatus for drilling, completing and Working-over a well wherein boththe well casinghead and the various well components secured thereto orsuspended therefrom are located underwater at a depth suflicient toallow ships to pass over them. Preferably, the casinghead and itsassociatcd equipment are located close to the ocean floor. In order toinstall equipment of this type under water in depths greater than theshallow depth at which a diver can easily operate, it has been necessaryto design ontirely new equipment for this purpose.

In one such method of drilling off-shore wells wherein :a wellhead basestructure is positioned on the ocean floor, strings of pipe, made up ofmany sections of pipe fastened together, are stripped in and out of thewell by the method and apparatus of the present invention.

It is the primary object of the present invention to provide a methodand apparatus, the apparatus being simple in design and easy to operate,whereby a larger internal-diameter pipe may be stripped into a well overa smaller diameter pipe or a well tool of smaller diameter.

A further ob ect of the present invention is to provide apparatus forstripping pipe into an offshore well from a platform positioned abovethe ocean surface, while maintaining a constant tension on an inner pipestring of smaller diameter over which the larger diameter pipe string isbeing stripped.

Another object of the present invention is to provide simple and safeapparatus adapted to be connected to and locked on an inner string ofpipe to be held in constant tension while an outer string of pipe isstripped over it.

These and other objects of this invention will be understood from thefollowing description taken with reference to the drawing, wherein:

FIGURE 1 is a longitudinal diagrammatic view illus trating cut-awaysections of a derrick together with the hoist systems mounted in thederrick in accordance with the present invention;

FIGURE 2 is a longitudinal view taken in partial cross section of oneform of a connector base to which a connector element has been securedand locked;

FIGURE 3 is a plan view of the apparatus shown in FIGURE 2;

FIGURES 4 and 5 are isometric views of the connector element andconnector base, respectively, illustrated inFIGURE 2; l

FIGURE 6 is a fragmentary isometric view illustrating the locking sleevenormally carried in the connector base of FEGURE 2;

FEGURES 7 through ll are schematic views illustrat ing the stepwiseoperations of carrying out the method of the present invention;

FIGURES -12 and 14 are longitudinal views of alternate forms of aconnector base in accordance with the present invention;

FIGURES 13 and 15 are longitudinal views of alternate forms of connectordevices adapted to engage in cooperatin g engagement with the connectorbases of FIGURES 12 and l4, respectively; and

FIGURE 16 is a plan View taken along the line 1o-l6 of FIGURE 14.

Referring to FIGURE 1 of the drawing, numerals l1 and 12 representfragments of a well derrick, such for example as the type used indrilling wells, which would extend down to an operational base or floor13, which may be the floor of a derrick or a door of a drillingplatform, either stationary or fioatable, as used in drilling offshorewells. The derrick 11- 12 is provided with a conventional hoist systemincluding a crown-block M, a traveling block '15 and fall lines 16.Secured to the lower end of the traveling block 15 are elevator links 17which suspend .a conventional elevator '18. The elevator 13 is designedto clamp around the upper end of a larger in ternal diameter pipe string2%, or a section thereof, for raising or lowering the pipe string.

The derrick lid-l2 is also provided with another pair of hoist systemscomprising hoists 21 and 22., hoist lines 23 and 2 sheaves 25 311E125,and connector elements 27 and 28 carried at the end of the hoist lines'23 and 2.4. in the event that the present hoist systems were mounted ona floating drilling barge adapted to move up and down with relation to awellhead positioned on the ocean floor, the hoists 2d and 22. would bepreferably constant tension hoists.

Positioned substantially axially withinthe larger diameter outer pipestring Eda is a smaller-diameter inner pipe string 39 having a connectorbase 31 secured to the top thereof which is adapted to be locked toeither of the connector elements 67 or 23. The pipe string Ztla isillustrated as extending through a hole 32 in the door of the derrick,and through a spider orrotary table 33 in which slips 34- are wed ed inorder to hang the pipe string 20a therefrom.

In FIGURE 2, one form of a connector base 3'1 comprises a body member-35 having an upwardly-extending mandrel section 35 of smaller diameter,with a pair of looking or latching lugs 37 and 38 formed on or fixedlysecured thereto. The lugs 37 and 38 are positioned diametricallyopposite each other on the mandrel as and extend outwardly therefrom.

The connector element 27 is illustrated as being provided with anopening 49 in the body thereof for receiving and locking therein onelug, in this case lug 37 of the conector base 31. The hoist cable 23 isfixedly secured to the top of the connector element 27 in any suitablemanner, as by a split thimble 41 and a lead upset 42. The opening ill ismore clearly shown in the isometric view of FIGURE 4. The upper end ofthe opening 46 is wider, as at lilo, than the lower portion at 46b, the

bottom of the connector element 27 being closed, as at 4-3, so as tosupport a locking lug 37 or 38 of the mandrel 326. As shown in FIGURE 5some of the wider portion 37:: of the lug 37 is adapted to pass throughthe wide opening 45a in the connector element 27 while the groovedportion 37b of the locking lug 37 is adapted to seat within the narrowopening 4% of the connector device 27.

To prevent the connector element 27 (FIGURE 2) from becoming accidentlyunlatched from the locking lug 37 of the connector base 31, theconnector base 31 is provided with suitable locking means which may takethe form of a sleeve 44 mounted in the top of the body member 35 forrotational movement about the mandrel 36. The locking sleeve 44 isretained in the body member 35 by means of a ring 45 or other suitablemeans. A spring 46 mounted within the body member 35 is adapted to bearagainst a flange 47 carried at the lower end of the sleeve 44 forpressing the flange 47 downwardly against a positioning ball ororienting element 48. These elements are more clearly shown in thedisassembled view of a portion of the connector base as shown in FIGURE6. Here it is shown that the bottom face of the flange 47 is providedwith a pair of diametrically-positioned grooves 50 and 51 which arealigned with the center line of a slot 52 cut in the side of the lockingsleeve 44 which extends downwardly from the top thereof, as illustrated.The sleeve 44 may be provided with one or more holes 53 extendingthrough the wall thereof into which a pin can be positioned for turningthe sleeve. The slot 52 in the locking sleeve 44 should be slightlywider than the widest part of either lociting lug 37 or 38 carried atthe upper end of the connector base 31. The height of the sleeve wouldbe such that, as shown in FIGURE 2, the sleeve 44 may be rotated underthe lower end 45 of the connector element 27 when it is engaged and withthe bottom of the locking lug 37 of the mandrel 36 thus locking theconnector element to the connector base 31. To unlock the connectordevice so that the connector element 27 can be detached from the lockinglug 37, the locking sleeve 44 would be rotated 180, or until the groove50 (FIGURE 6) seated on the ball 48, at which time the slot 52 in thelocking sleeve 44 would be positioned beneath the closed end 43 of theconnector element 27, allowing it to be moved downwardly into the slot52 at which time the enlarged portion 37a of the locking lug would beopposite the wide portion 4% of the opening 40 so that the connectorelement 27 could be removed laterally from the locking lug 37.

The lower end of the connector base 31 is provided with suitable means,such as screw threads 54, whereby the connector base 31 may be removablysecured to the top of the smaller-diameter inner pipe string 3% (FIGURE1). It is to be understood that any other suitable form of a device forlatching onto the inside or the outside of a pipe may be employed forsecuring the connector base 31 (FIGURE 2) to a smaller diameter tubularpipe string 34 or other elements over which pipe is to be stripped.Thus, for example, in FIGURE 12 a connector base 55 is illustrated asbeing provided diagrammatically with an internal pipe spear comprising apair of pivotallymounted spear arms and 61 having teeth 62 and 63thereon, respectively, and being suspended from the lower end of theconnector base 55. The mandrel 5'6 is actually slidable relative to thebase 55 and has fixedly secured to the lower end of the mandrel a Wedgeelement 64 adapted to contact tapered faces 65 and 66 on the spear arm60 and 61. Thus, on applying tension to the mandrel 56 the wedge element64 forces the teeth 62 and 63 against the inner surface of a pipe stringsurrounding it.

In the form of the connector base 55 shown in FIG- URE 12, the dualmandrel section 56-57 is provided With slots 67 and 68 therein forreceiving a locking lug '70 of a connector element 71 which would besecured to a cable '72. The form of the slots 67 and 68 of the apparatusin FIGURE 12 would be identical with the slots shown in FIGURE 4 itturned upside down. Another form of a connector base together withcooperating connector elements is shown in FIGURES 14, 15 and 16 ascomprising a connector base 74 having a mandrel 75 extending upwardlytherefrom in which a pair of locking recesses 76 and 77 are formed forreceiving hooks 73 of a suitable design for cooperating therein. Thehooks 78 would be carried by the connector elements 80 and 81.

In performing an operation in accordance with the present invention ofstripping a larger internal diameter pipe into a well over a smallerdiameter pipe, the operation would start as illustrated in FIGURE 7 withthe larger diameter pipe Zita being held by means of slips 34 in a fixedposition within the spider or rotary table 33. At the same time theconnector base 31 (FIGURE 2) would be secured to the top of the smallerdiameter pipe string 3% (FIGURE 7) with the connector element 28 securedto the lower end of hoist line 24, being connected to one lug of theconnector base 31 so that the tension on the cable 24 could hold theconnector base Ell above the upper end of the pipe string Zita. Withconnector element 28 and its hoist cable 24 being employed in thismanner, the other connector element and its cable 23 {FIGURE 7) would berun down another section of pipe 23 which is to be added to pipe 2%:already suspended from slip 34. The elevator 18 would be connected toone end of the pipe section 2%) to be added and it would be hoisted to aposition shown in FIGURE 8 by means of the main hoist system of thederrick. With the new section 29 of pipe suspended in this position, theconnector element 27 extending therethrough would be carried overmanually to the locking lug 37 and locked thereon as shown in FIGURE 9.At this time the pipe section 29 and the cable 23 carried therein wouldbe moved into substantially longitudinal relationship with the pipestring Ztia already in the well, as shown in FIGURE 10. Tension wouldthen be applied to cable 23 and its connector element by means of thehoist 21 (FIGURE 1), at which time the weight of the inner pipe string34) would be transferred from connector element 28 to connector element27. With the cable 23 and its connector element 27 now supporting theinner pipe string 30, the other connector element 28 and its cable 24are disconnected from the locking lug 38 of the connector base 31 andremoved therefrom.

The additional section of pipe 20 is then lowered down over the cable,connector element 27, connector base 21 and inner pipe string 30 untilthe threads 82 at the lower end of the pipe section 20 engage thethreads in the upper section of the pipe 20a and may be rotated therein,for coupling the two pipe sections together. While this operation isgoing the other connector element 28 and its cable 24 may be run downthrough another section pipe to be added to the larger internal diameterpipe string, as shown in FIGURE 7. After the new section 259 (FIG- URE11) was secured to the pipe string 20a, the slips 34 would be removedwhile the elevator 18 (FIGURE 1) supported the larger internal diameterpipe string and lowered it into the well until the connector base 31 wasabove the upper end of the larger internal diameter pipe string, asshown in FIGURE 7, at which time the slips 34 would again be insertedaround the pipe string 20a to suspend it in place. By repeating thecycle of operation described, the desired amount of pipe may be strippedinto a well. It may be seen that since the pipe section 20 must bepositioned vertically above the pipe section 2001, the sheaves 25 and 26(FIGURE 1) must be positioned on the derrick at a height sufiicient toaccommodate a pipe section in the manner described.

To remove a larger diameter pipe from a well and strip it out of asmaller diameter pipe, the above-described procedure would be reversed.After connector element 27 was secured to the connector base, the upperpipe section 24] would be raised by means of elevator 18 (FIG- URE 1)and unscrewed and elevated from that section Etta, to expose theconnector base 31 as shown in FIG- URE 11. The connector device 28 wouldthen be brought into position and latched on the connector base 31 andtension applied to its cable 24 to pick up the Weight of 3 the innerpipe string 30, as shown in FIGURE 16. Connector 27 would then bedetached from the connector base 31, as shown in FIGURE 8, and theconnector device 27 and its cable 23 would be pulled out of the pipesection 29, as shown in FlGURE 7, While the other cable 24 and itsconnector device 28 supported the inner pipe string ii.

We claim as our invention: 1. A method of stripping a larger internaldiameter outer pipe string over a smailer diameter inner elongatedmember, said method comprising the sequential steps of connecting afirst suspending cable to said inner member, applying tension to saidfirst cable to suspend said inner member therefrom, running a secondcable through a section of larger internal diameter outer pipe to beadded to the top of said previously positioned outer pipe string,connecting said second cable to said inner-member, moving said pipesection to be added and said second cable carried therein intosubstantial longitudinal position above said suspended outer pipestring, applying tension to said second cable to suspend said innermember therefrom, disconnecting said first cable from said inner member,

lowering said larger internal diameter pipe section into to said firstcable to suspend said inner member therefrom,

running a second cable through a section of larger inte nal diameterouter pipe to be added to the top of said outer pipe string, connectingthe lower end of said second cable to said inner member, moving saidpipe section to be added and said second cable carried therein intosubstantial longitudinal position above said suspended outer pipe stringapplying tension to said second cable to suspend said inner membertherefrom, disconnecting said first cable from said inner member,lowering said larger internal diameter pipe section into engagement withsaid outer pipe string, connecting the pipe section to said pipe string,and lowering said outer pipe string until the top of the inner memberemerges therefrom.

3. A method of stripping a larger internal diameter outer pipe stringover a smaller diameter inner pipe string, said method comprising thesequential steps of fixedly suspending said outer pipe string, attachinga dual connector base to the top of the inner pipe string, connecting afirst suspending cable to said connector base, applying tension to saidfirst cable to suspend said inner pipe string therefrom, running asecond cable through a section of larger internal diameter outer pipe tobe added to the top of said outer pipe string, connecting the lower endof said second cable to said connector base, moving said outer pipesection to be added and said second cable carried therein intosubstantial longitudinal position above said suspended outer pipestring, applying tension to said second cable to suspend said inner pipestring therefrom, disconnecting said first cable from said connectorbase, lowering said larger internal diameter pipe section intoengagement with said outer pipe string and connecting the pipe sectionto said outer pipe string.

4. A method of stripping a larger internal diameter outer pipe stringover a smaller diameter inner pipe string, said method comprising thesequential steps of fixedly suspending said outer pipe string, attachinga dual con nector base to the top of the inner pipe string, connecting afirst suspending cable to one side of said connector base, applyingtension to said first cable to suspend said inner pipe therefrom,running a second cable through a section or" larger internal diameterouter pipe to be added to the top of said outer pipe string, connectingthe lower end of said second cable to the other side of said connectorbase, moving said outer pipe section to be added and said second cablecarried therein into substantial longitudinal position above saidsuspended outer pipe string, applying tension to said second cable tosuspend said inner pipe string therefrom, disconnecting said first cablefrom said con nector base, lowering said larger internal diameter pipesection into engagement with said outer pipe string and connecting thepipe section to said outer pipe string, lowering said outer pipe stringuntil the connector base at the top of the inner pipe string emergestherefrom, and anchoring said outer pipe string against axial movement.

5. Apparatus for use in oil well operations for selectively stripping toand from a well a larger internal diameter vertical outer pipe stringover a smaller diameter elongated inner member held in tenisonthroughout the operation, said apparatus comprising first and second andthird hoist means having respectively first and second and third hoistcable means with first and second and third connector means carriedthereby, said first connector means being pipe connector means of a sizeto'connect onto the upper end of the larger internal diameter outer pipestring, an operational base including support means for mounting all ofsaid hoist means thereabove, and slip-type anchoring means for engagingthe larger internal diameter outer pipe string and temporarily securingit relative to said base against downward axial movement, said secondand third connector means being connectible to said inner member and ofa size to pass through said outer pipe string.

6. Apparatus for use in oil well operations for selectively stripping toand from a well a larger internal diameter vertical outer pipe stringover a smaller diameter vertical inner pipe string held in tensionthroughout the operation, said apparatus comprising first and second andthird hoist means having respectively first and second and third hoistcable means with first and second and third pipe connector means carriedthereby, said first connector means being elevator means of a size toconnect onto the upper end of the larger internal diameter outer pipestring, an operational base including support means for mounting all ofsaid hoist means thereabove, and slip-type anchoring means for engagingthe upperend of the larger internal diameter outer pipe string andtemporarily securing it to said base against downward axial movement,said second and third pipe connector means being connectible to saidinner pipe string and of asize to pass through said outer pipe string.

7. Apparatus for use in oil well operations, for selectiveiy strippingto and from a well a larger internal-diameter vertical outer pipe stringone section at a time over a smaller-diameter vertical inner pipe stringheld in constant tension throughout the operation, said apparatuscomprising first and second and third hoist means hav ing respectivelyfirst and second and third hoist cable means with first and second andthird pipe connector cans carried thereby, said first connector meansbeing elevator means of a size to connect onto the upper end of thelarger internal diameter outer pipe string, an operational baseincluding support means for mounting ail of said hoist means thereabove,slip-type anchoring means for engaging the upper end of the largerinternal diameter outer pipe string and temporarily securing it to saidbase against downward axial movement, and a connector base includingmeans for securing it temporarily tothe upper end of the smallendiameterinner pipe string, said connector base including cooperating engagingmeans adapted to connect releasably to said second and third conhectormeans carried by said second and third hoist means, said second andthird connector means and said connector base being of a size to passthrough said outer pipe string. i

8. Apparatus for use in oil well operations for selectively strippinginto and out of a well a larger internal diameter vertical outer pipestring one section at a time over a smaller-diameter vertical inner pipestring held in constant tension throughout the operation, said apparatuscomprising first and second and third hoist means having respectivelyfirst and second and third hoist cable means with first and second andthird pipe connector means carried thereby, said first connector meansbeing elevator means of a size to connect onto the upper end of thelarger international diameter outer pipe string, an operational baseincluding support means for mounting all of said hoist means thereabove,slip-type anchoring means for engaging the upper end of the largerinternal diameter outer pipe string and temporarily securing it to saidbase against downward axial movement, a connector base including meansfor securing it temporarily to the upper end of the smaller-diameterinner pipe string, said connector base including cooperating engagingmeans adapted to receive said second and third connector means carriedby said connector base for selectively locking one of said second andthird connector means thereto, said second and third connector means andsaid connector base being of a size to pass through said outer pipestring, said second and hoist cable means being slightly greater inlength than the length of a section of said outer larger internaldiameter pipe.

9. A method of stripping a larger internal diameter outer pipe stringover a smaller diameter inner elongated member, said method comprisingthe sequential steps of fixedly suspending said outer pipe string,connecting a first suspending cable to said inner elongated member,applying tension to said first cable to suspend said inner membertherefrom, raising the outer pipe string with said first cable inside ituntil at least one section thereof is above its previously-suspendedposition, again fixedly suspending said outer pipe string, disconnectingat least one pipe section from the top of said outer pipe string,raising said disconnected pipe section until at least the top of theinner member is exposed therebelow, connecting a second cable to theinner member, moving said second cable into a substantially longitudinalposition outside said disconnected pipe section, applying tension tosaid second cable to suspend said inner member therefrom, anddisconnecting said first cable from said inner member.

10. A method of stripping a larger internal diameter outer pipe stringover a smaller diameter inner elongated member, said method comprisingthe sequential steps of fixedly suspending said outer pipe string,attaching a dual connector base to the top of the inner member,connecting a first suspending cable to said connector base, applyingtension to said first cable to suspend said inner membertherefrom,raising the outer pipe string with said first cable inside it until atleast one section thereof is above its previously suspended position,again fixedly suspending said outer pipe string, disconnecting at leastone pipe section from the top of said outer pipe string,

raising said disconnected pipe section until the connector base at thetop of the inner member is exposed therebelow, connecting a second cableto said connector base, moving said second cable into a substantiallylongitudinal position outside said disconnected pipe section, applyingtension to said second cable to suspend said inner member therefrom,disconnecting said first cable from said connector base, moving saidlarger internal diameter pipe section to one side of said suspended pipestring, and Withdrawing said first cable from said pipe section.

11. A method of stripping a larger internal diameter outer pipe stringover a smaller-diameter inner pipe string, said method comprising thesequential steps of fixedly suspending said outer pipe string,connecting a first suspending cable to said inner pipe string, applyingtension to said first cable to suspend said inner pipe string therefrom,raising the outer pipe string with said first cable inside it until atleast one section thereof is above its previously suspended position,again fixedly suspending said outer pipe string, disconnecting at leastone pipe section from the top of said outer pipe string, raising saiddisconnected pipe section until at least the top of the inner pipestring is exposed therebelow, connecting a second cable to said innerpipe string, moving said second cable into a substantially longitudinalposition outside said disconnected pipe section, applying tension tosaid second cable to suspend said inner pipe string therefrom, anddisconnecting said first cable from said inner pipe string.

12. A method of stripping a larger internal diameter outer pipe stringover a smaller diameter inner pipe string being held in tension, saidmethod comprising the sequential steps of fixedly suspending both pipestrings, attaching a dual connector base to the top of the inner pipestring, connecting a first suspending cable to one side of saidconnector base, applying constant tension to said first cable to suspendsaid inner pipe string therefrom,

raising the outer pipe string with said first cable inside it 7 until atleast one section thereof is above its previously suspended position,again fixedly suspending said outer pipe string, disconnecting at leastone pipe section from the top of said outer pipe string, raising saiddisconnected pipe section until the connector base at the top of theinner pipe string is exposed therebelow, connecting the lower end of asecond cable to the other side of said connector base, moving saidsecond cable into a substantially longitudinal position outside saiddisconnected pipe section, applying tension to said second cable tosuspend said inner pipe string therefrom disconnecting said first cablefrom said connector base, moving said larger internal diameter pipesection to one side of said suspended pipe strings, and withdrawing saidfirst cable from said pipe section.

13. A method of stripping a larger internal-diameter outer pipe stringover a smaller-diameter inner elongated member, said method comprisingthe sequential steps of (a) connecting a first suspending element tosaid inner member to suspend said inner member relative to said largeinternal-diameter outer pipe string,

(b) running a second suspending element through a section of largerinternal-diameter outer pipe to be added to the top of said outer pipestring,

(0) suspending and moving said pipe section to be added and said secondsuspending element carried therein into substantial longitudinalposition above said suspended outer pipe string,

(d) connecting said second suspending element to said inner member,

(e) transferring the weight of said inner member from said firstsuspending element to said second suspending element,

(7) disconnecting said first suspending element from engagement withsaid inner member,

(g) lowering said larger internal-diameter pipe section into engagementwith said outer pipe string while maintaining said inner member intension within said outer pipe string, and

(h) connecting the pipe section to the pipe string.

14. The method of claim 1 wherein the weight of said inner member istransferred to said second suspending element by applying tension tosaid second suspending element.

15. A connector system having one member carried at one end of asubstantially vertical elongated member for selectively securing one ofa pair of cooperating members thereto, said connector system comprisinga latch-carrying body member having latch means carried thereby and acooperating latch-receiving body member, one each of one of said bodymembers carried at the end of each of a pair of cable means, and meansremovably securing said other body member to one end of an elongatedmember, one of said body members being adapted to latchingly receive twoof said other body members.

16. A connector system having one member carried at the upper end of asubstantially vertical elongated member for selectively securing one ofa pair of cooperating members thereto, said connector system comprisinga 9 latchcarrying body member having latch means carried thereby and acooperating latch-receiving body member, one each of one of said bodymembers carried at the end of each of a pair of hoist cable means, hoistmeans having said hoist cable means secured thereto for applying tensionthereto, means fixedly securing one of said other body members to'theupper end of said elongated member, one of said body members beingadapted to latchingly receive two of said other body members.

17. A connector system having one member carried at the upper end of asubstantially vertical section of pipe for selectively securing one of apair of cooperating members thereto, said connector system comprising alatch-carrying body member having latch means carried thereby and acooperating latch receiving body member, one each of one of said bodymembers carried at the end of each of a pair of hoist cable means, hoistmeans having said hoist cable means secured thereto for applying tensionthereto, means fixedly securing one of said body members to the end ofeach of said hoist cable means, and means removably securing said otherbody member to one end of a string of pipe, one of said body membersbeing adapted to latchingly receive two of said other body members.

18. A connector system having one portion carried at the upper end of asubstantially vertical section of pipe for selectively securingone of apair of cooperating latching elements thereto, said connector systemcomprising latch-carrying body members having latch means carriedthereby and a cooperating, latch-receiving body member, one of saidlatch-carrying body members car tied at the end of each of a pair ofhoist cable means, hoist means having said hoist cable means securedthereto for maintaining constant tension thereon, and means removablysecuring said latch receiving body member to one end of a string ofpipe, said latch-receiving body being adapted to receive two of saidlatch-carrying body members.

CHARLES E. OCONNELL, PrimaryExaminer.

BENJAMIN BENDETT, Examiner.

1. A METHOD OF STRIPPING A LARGE INTERNAL DIAMETER OUTER PIPE STRINGOVER A SMALLER DIAMETER INNER ELONGATED MEMBER, SAID METHOD COMPRISINGTHE SEQUENTIAL STEPS OF CONNECTING A FIRST SUSPENDING CABLE TO SAIDINNER MEMBER, APPLYING TENSION TO SAID FIRST CABLE TO SUSPEND SAID INNERMEMBER THEREFROM, RUNNING A SECOND CABLE THROUGH A SECTION OF LARGERINTERNAL DIAMETER OUTER PIPE TO BE ADDED TO THE TOP OF SAID PREVIOUSLYPOSITIONED OUTER PIPE STRING, CONNECTING SAID SECOND CABLE TO SAIDINNER-MEMEBR, MOV-